The effect of friction in the thermal convection instability of granular fluids is studied by means of molecular dynamics simulations. It is found that the transitions between different convective states (zero, one, and two rolls) are primarily governed by the average energy loss per collisions and not by the friction and restitution coefficients separately, and can be roughly described in term...

We investigate the free cooling of inelastic rough spheres in the presence of Coulomb friction. Depending on the coefficients of normal restitution ǫ and Coulomb friction μ, we find qualitatively different asymptotic states. For nearly complete normal restitution (ǫ close to 1) and large μ, friction does not change the cooling properties qualitatively compared to a constant coefficient of tange...

Perspectives Travaux sur le lancer de photons Amélioration de la répartition des photons dans le volume. Accélération de la recherche dans la carte. Cache dans le volume Cohérence spatiale à l'aide d'enregistrements volumiques. Milieux anisotropes Fonctions de phase (Henyey-Greenstein, Schlick...) Restitution réaliste des résultats Prise en compte du support de restitution. Exploitation de la c...

We revisit our recent contribution [2] and give two simpler proofs of the socalled Haff’s law for granular gases (with non-necessarily constant restitution coefficient). The first proof is based upon the use of entropy and asserts that Haff’s law holds whenever the initial datum is of finite entropy. The second proof uses only the moments of the solutions and holds in some weakly inelasticity r...

El presente artículo pretende dilucidar las razones fundamentales sobre que Andrés Bello baso su decisión de no incluir y derogar la institución restitutio in integrum proveniente del Derecho Indiano al redactar el Código Civil. Se analizará además significado implicaciones “Ley efecto retroactivo” promulgada en 1861- es decir, tan solo cuatro años después código haya entrado vigencia- cual hac...

The debate over the restitution of cultural property is usually framed as dispute between what John Henry Merryman defined ‘cultural nationalism’ and internationalism’: opposite viewpoints that argue whether heritage objects should be returned to their countries origin or spread around world determined by other principles. I argue, however, concepts are problematic both in definition perception...

We report numerical simulations of strongly vibrated granular materials designed to mimic recent experiments performed in both the presence and the absence of gravity. The coefficient of restitution used here depends on the impact velocity by taking into account both the viscoelastic and plastic deformations of particles, occurring at low and high velocities, respectively. We show that this mod...

Restitution, the characteristic shortening of action potential duration (APD) with increased heart rate, has been studied extensively because of its purported link to the onset of fibrillation. Restitution is often represented in the form of mapping models where APD is a function of previous diastolic intervals (DIs) and/or APDs, A(n+1)=F(D(n),A(n),D(n-1),A(n-1),...), where A(n+1) is the APD fo...

A beat-to-beat alternation in the action potential duration (APD) of myocytes, i.e. alternans, is believed to be a direct precursor of ventricular fibrillation in the whole heart. A common approach for the prediction of alternans is to construct the restitution curve, which is the nonlinear functional relationship between the APD and the preceding diastolic interval (DI). It was proposed that a...

Action potential duration and contractility are reduced following premature excitations, and gradually increase as the stimulus interval is lengthened. To examine these phenomena of electrical and mechanical restitution in the human heart, we simultaneously measured action potential duration and the maximum rate of left ventricular pressure in five patients undergoing electrophysiological study...